1- For that one I'll let smed79 decide. My only concern about this is that in the bundled list (with EasyList and Liste FR), there will be two lines "Dernière modification le [...]", and that might confuse some users.

2- I'm not sure but that might be because of the Arabic characters. How often do you have this issue? I personally never encountered it.
When this happens again, please give us the time (UTC) when the last download failed.

I do not think it is useful for AR List, add the date in the list only create redundancy with EasyList.
I suggest to use bundled list "Liste AR+Liste FR+EasyList" http://adblockplus.org/en/subscriptions